Take a look at the
official development guide
for Sage. At a minimum, the first chapter in that guide is required
reading for any Sage developer. Also pay special attention to the
trac guidelines.
You can also join the
sage-devel
mailing list or hang around on the
#sage-devel IRC channel on
freenode. While you are getting to know
the community, grab a copy of the Sage
source and familiarize yourself with the
git version control system.

The best way to become familiar with the Sage development process is
to choose a ticket from the
trac server
and review the proposed changes contained in that ticket. If you want
to implement something, it is a good practice to discuss your ideas on
the sage-devel mailing list first, so that other developers have a
chance to comment on your ideas/proposals. They are pretty open to new
ideas, too, as all mathematicians should be.

Sage’s main programming language is
Python.
Some parts of Sage may be written in other languages, especially the
components that do the heavy number crunching, but most native
functionality is done using Python, including “glue code”. One of the
good aspects of Python that Sage inherits is that working code is
considered more valuable than merely fast code. Fast code is valuable,
but clean, readable code is important. In the mathematics community,
inaccurate results are unacceptable. Correctness comes before
optimization. In the following paper

If you want, you can
try to learn Python by using Sage. However,
it is helpful to know what is pure Python and when Sage is doing its
“magic”. There are many things that work in Python but not in Sage,
and vice versa. Furthermore, even when the syntax is identical, many
programming concepts are explained more thoroughly in Python-centered
resources than in Sage-centered resources; in the latter,
mathematics is usually the priority.

Absolutely! If you want to write code for Sage or update the
official documentation,
you will need your own installation of Sage on SageMathCloud.
You can find more information about the details of installation in
the SageMathCloud FAQ.

Yes. As with any free open source software project, there are numerous
ways in which you could help out within the Sage community, and
programming is only one of many ways to contribute.

Many people like writing technical tutorials. One of the joys of doing
so is that you also learn something new in the process. At the same
time, you communicate your knowledge to beginners, a skill which is
useful in fields other than technical writing itself. A main point
about technical writing is that you communicate a technical subject to
beginners, so keep technical jargon to a minimum. Darrell Anderson
has written some
tips on technical writing,
which we highly recommend.

For the graphic designers or the artistically creative, you can
help out with improving the design of the Sage website. Or you can
cast your critical artistic eyes over the interfaces of SageMathCloud
or the Sage notebook, and find out where they need improvement.

If you can speak, read,
and write in another (natural) language, there are many ways in which
your contribution would be very valuable to the whole Sage
community. Say you know Italian. Then you can write a Sage tutorial in
Italian, or help out with translating the official Sage tutorial to
Italian.

The above is a very short
list. There are many, many more ways in which you can help out. Feel
free to send an email to the
sage-devel
mailing list to ask about possible ways in which you could help out,
or to suggest a project idea.

I submitted a bug fix to the trac server several weeks ago. Why are you ignoring my patch?¶

We are not trying to ignore your patch. People who work on Sage do so
in their free time. With hundreds of open tickets of varying degrees of
impacts on the whole Sage community, people who work on tickets need
to prioritize their time and work on those tickets that interest
them. Sometimes you may be the only person who understands your
patch. In that case, you are encouraged to take extra care to make it
as easy as possible for anyone to review your patch. Here are some
tips on making your patch easy to review:

Have you clearly described the problem your patch is trying to
solve?

Have you provided any background information relevant to the problem
your patch is trying to solve? Such information include links to
online resources and any relevant papers, books and reference
materials.

Have you clearly described how your patch solves the problem under
consideration?

Have you clearly described how to test the changes in your patch?

Have you listed any tickets that your patch depends on?

If there are more than one patch, have you clearly stated the order
in which those patches are to be applied?

If your patch stands no chance of being merged in the Sage source
tree, we will not ignore your patch but simply close the relevant
ticket with an explanation why we cannot include your changes.

When and how might I remind the Sage community of a patch I care about?¶

You are encouraged to take extra care in how you remind the Sage
community of a patch you want to get merged into the Sage source
tree. There might be an upcoming bug squash sprint or an upcoming Sage
Days workshop that relates to your patch. Monitor the relevant Sage
mailing lists and respond politely to any relevant email threads, with
clear explanation on why your patch is relevant. Monitor the
#sage-devel IRC channel, taking care to strategically time your
reminders.

I wrote some Sage code and I want it to be integrated into Sage. However, after renaming my file a.sage to a.py, I got syntax errors. Do I have to rewrite all my code in Python instead of Sage?¶

The basic answer is yes, but rewriting is a big word for what is
really needed. There is little work to do since Sage mostly follows
Python syntax. The two main differences are handling of integer (see
also the afterword for more on the sage preparser), and the
necessity to import what you need.

If you need to return an integer to the user, write returnInteger(1) instead of return1. In Python, 1 is a python
int, and Integer(1) is a Sage/Gmp integer. In addition,
Integer are much more powerful than int; for
example, they know about being prime and factorization.

You should also notice that 2/3 no longer means
Integer(2)/Integer(3) and returns 2/3, but rather
int(2)/int(3), and therefore returns 0 due to integer
division where it deregards any remainder. If you are dealing with
Integer but you really need an integer division you can use
Integer(2)//Integer(3).

Importing stuff: The second big change is the necessity to
import everything what you need. More precisely, each time you use
some Sage function, you need to import it at the beginning of the
file. For example, if you want PolynomialRing, you need to
write: